Two lines are perpendicular. The equation of the first line is y = 4x + 1. Which of the following cannot be the equation of the second line?
A.
2003-10-04-00-00_files/i0160000.jpg
B.
x – 4y = –2
C.
x + 4y = 2
D.
8y = –2x – 5

Question

Two lines are perpendicular. The equation of the first line is y = 4x + 1. Which of the following cannot be the equation of the second line?
A.
2003-10-04-00-00_files/i0160000.jpg
B.
x – 4y = –2
C.
x + 4y = 2
D.
8y = –2x – 5

mrnood · Answer

in the standard form of the straight line equation
y=mx+c

The gradient is given by m
so  your equation y=4x+1
tells you that the gradient is 4

A perpendicular line has gradient -1/m

So
Arrange all the equations in standard form (y=mx+c)

Any line which IS perpendicular to y=4x+1 must have a gradient equal to -1/4